How to build your own WaveGuide Antenna (Cantenna) for 802.11b/g Wireless Networking and other 2.4GHz Applications
Building a WaveGuide Antenna, also known as a Cantenna, is a fun and rewarding exercise for those interested in getting more range out of their
stock 802.11b/g wireless networking equipment. The concept is fairly simple - a "standard" radiating antenna transmits and receives RF energy
in all directions. If you put the same antenna inside a metal enclosure in the shape of a can, with one end of the can open, then the RF energy
is directed out the open end of the can. This increases the gain of the antenna by 3 or more times in the direction that the open end
of the can is pointing. In a nutshell, you will get much greater range, and block out interference that may be coming in from other directions.
Here is what you need to build your own Cantenna:
A tin can. Just about any can will do. Use the calculator below to make sure it will work.
Some basic tools including a can opener, ruler, drill with 5/8" bit, awl or nail for punching guide holes, and a marker.
Doing the math:
Use the calculator below to check your can size and find out where you are going to mount your connector. The ideal can is between 3 and 4 inches
in diameter, although other size cans will work too. Also, the longer the can, the greater the gain you will have.
Let's get building!
Using your can opener, remove one end of the can. Hopefully everything will be nice and smooth, but if not, remove any burrs so you don't cut yourself
later on. Empty the contents of the can and wash it out. You can leave the outside label on if you want, that's up to you.
Using the calculator above and your ruler, mark the 1/4 Guide Wavelength measurement from the rear of the can (the side that still has the end)
Using an awl, punch, or nail, punch a pilot hole at the location of the mark you just made
Reach inside and install the washer and nut on the connector and tighten in place. You may need to use some pliers to complete this step
.
You are done! Wasn't that easy? Connect up your pigtail to your wireless card or access point and start testing! I will leave it up to you
to find the best way to mount your cantenna. It is okay to drill into the can to attach a mount. Nuts and bolts on the inside are okay, as
long as they don't stick out on the inside too much.
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